Finding Geothermal Energy Just Got Easy

The ground beneath your feet contains energy, vast sums of energy. It has been estimated that in the U.S. alone the geothermal energy resources are enough to power the entire U.S. for 30,000 years. Yet, there are serious questions about geothermal energy development. It has been named the 'poor cousin' of renewable energy: likely because it is mining a finite resource and there is the little issue of causing earthquakes. Yet it is also a non-polluting, constant source of energy that is readily available using todays technology.

No matter if you decide it is a good option or not, one outstanding problem with geothermal energy is that it can actually be tricky to find. Sure, we have 'heat' maps like the one shown below (the fold), but the only surefire way to tell if geothermal energy sources are easily available is to drill, which can be an expensive endeavor. Now scientists have found an easy way to tell if geothermal energy could be bubbling up in your neck of the woods.

"We wanted to show that certain surface indicators, specifically the ratio of helium isotopes, can be used to identify areas with high resource potential for geothermal energy," says van Soest, co-author of a research report that appears in the Nov. 30 issue of the scientific journal Science.

The Earth's crust and mantle differ in their ratio of helium isotopes. Usually, helium-4 is more abundant in the crust, and helium-3 is more abundant in the mantle. So, the research team looked to see if the water at known geothermal areas contained a different ratio of helium isotopes.

"When we found the elevated ratios, we knew that the only way these waters could be enriched with helium-3 was if they had interacted with fluids from the Earth's mantle," explains van Soest.

Thus, to find a geothermal hot spot for energy generation, measure the helium isotope ratio in groundwater, and if it is high in helium-3 you have yourself a potential spot to drill. This technique could be used to map the potential of geothermal areas, and determine where geothermal technology will be most effective, hopefully with the least environmental damage, or seismic risk.

Although geothermal is not without its own long-term consequences, this research may go a considerable distance to ensure a safer, and more readily available energy source in the near future.